1. Field of the Invention
This invention relates to a terminal for electric wire welding suitable for a use of connecting a wire to a terminal in the manufacturing process of an electric or electronic device, such as electromagnetic relay or the like, and a welding torch suitable for electric wire welding to the terminal.
2. Description of the Prior Art
According to a conventional coil wire and terminal connection method in manufacturing an electromagnet for a small size relay, one end of the coil wire wound around a spool is wrapped around a wrapping terminal projecting from a flange of the spool to be fixed by soldering. The soldering is performed by dipping the wrapping terminal wound by the coil wire into fusion solder. The conventional wrapping terminal has a simple rod-shaped projection. Since the conventional connection method of the wrapping terminal employs solder, environmental pollution with lead is a concern.
Instead of the above-mentioned connection employing solder, the adoption of arc welding free from environmental pollution with lead has been examined. A model of a conventional connection method of a wrapping terminal by arc welding is embodied in FIG. 4 which shows a torch 1 providing an arc welding machine, a support member 2 for supporting the torch, a direct current power supply 3 for the arc welding machine, a spool 4 wound by a coil wire 7, flanges 4a disposed on both ends of the spool 4, wrapping terminals 5 planted on the spool 4 and wrapped by ends of the coil wire 7, an electrode probe 6 for fixing the potential of the wrapping terminals 5 toward positive potential prior to welding, and lower projections 8 electrically conductive with the terminals 5.
The arc welding connection method requires, as a preceding procedure to the execution of welding, a first production process in which the wrapping terminal 5 is vertically positioned upward and the support member 2 is moved up and down as shown by an arrow mark 10 to position a top end of an electrode rod 9 held by the torch 1 near a top end of the terminals 5, and a second production process in which the probe 6 is horizontally moved forward-and-backward as shown by an arrow mark 11 to bring the end of the probe 6 into contact with the lower projection 8.
The above-mentioned method requires two positioning mechanisms for positioning the vertical orientation of the electrode rod 9 and the horizontal direction of the probe 6, and the framing of the welding arrangement becomes complicated. Since the two step positioning process is necessary before welding, productivity is lowered.